Summer’s Here, Protect Your Skin
By Larry Bishop, MD // June 11, 2012
THE 411 ON SUNSCREEN
ABOVE VIDEO: The FDA updates consumers on facts related to choosing and using sunscreen. (Video by the Food and Drug Administration)
BREVARD COUNTY • VIERA, FLORIDA – There are probably very few subjects as difficult to understand as sunscreen. Nearly every time I go to Walgreens, I see someone standing in front of the sunscreen aisle with a look of confusion on their face. What works? What doesn’t work? Do sunscreens cause cancer? With this article, I am going to clear all the confusion, and give you the tools you need to make good decisions.
First, the facts. We know that ultraviolet light causes skin cancer. The evidence is irrefutable, due to our ability to analyze the genetic damage in nearly all types of skin cancers. Additionally, we have epidemiologic data which support the concept that people who get increased doses of ultraviolet light, either from natural sources (i.e. the sun) or from artificial sources such as tanning beds, will get increased numbers of skin cancers.
Avoid UV Exposure
What are our defenses against skin-damaging ultraviolet light? The first, and most obvious, is to avoid UV exposure, particularly during the peak hours of ultraviolet radiation which are between 10 AM and 3 PM. Additionally, wearing protective clothing and hats that shield not only the front of the face but also the side of the face is very helpful. Unfortunately though, fashion and comfort sometimes preclude the wearing of long garments.
That is where sunscreen comes in. We used to make a distinction between sunscreens, compounds which absorb ultraviolet light, and sun blocks, which reflect UV rays. Now, many of the commercial products that are available to us have both types of ingredients in them. For instance, many contain zinc oxide or titanium dioxide, and also contain other products which chemically absorb ultraviolet light.
Check SPF and Ingredients
How do we evaluate a sunscreen for effectiveness? Perhaps the most important of all factors is the SPF, which stands for sun protection factor. Sun protection factor is the number that expresses the relative effectiveness of a particular sunscreen. The number is derived by exposing volunteers to various doses of ultraviolet light and determining how long it takes to cause redness of the skin with and without sunscreen.
For example, if a fair-skinned individual was exposed to the midday sun in an equatorial region, redness could occur after as little as 15 min. If that same person used sunscreen with an SPF 30, (and frequently reapplied according to directions) it would theoretically take 7.5 hours–30 times as long–to get the same redness of skin, and the same amount of DNA damage. Interestingly, there is strong data to support the contention that any SPF greater than 30 really does not provide significant incremental protection.
There are other factors to consider, however. For one thing, the SPF factor does not address ultraviolet A protection. We know that ultraviolet A is important as a carcinogen, albeit a less potent carcinogen that ultraviolet B, and is also strongly implicated in causing the damage we associate with aging skin. Even though there are many products that advertise broad-spectrum UVA/UVB protection, if they do not contain zinc oxide, avobenzone, or ecamsule (also known as Mexoryl SX), they may not provide adequate UVA protection. Titanium dioxide may also provide UVA protection, but recent research has raised questions about the safety of nanoparticle titanium dioxide.
Apply Early and Reapply
Other factors which dictate the success or failure of a skin protection regimen include timing of application, amount of sunscreen applied, as well as exposure to sweating, water, or the rubbing of clothing. No matter which sunscreen you use, it is far more effective if you apply it 30 to 45 minutes before going into the sun. That interval gives the sunscreen a chance to bond with your skin cells and allows the entire dose to be absorbed, rather than rub or be sweated off.
Because sunscreens go through chemical degradation when they are exposed to UV light, frequent reapplication is also important, and, ideally, should be done every two hours. There are, however, sunscreens that seem to be more persistent in action than others. For instance, Bull Frog sunscreen is noted for its persistence. I am an avid cyclist, and Bull Frog Marathon Mist is my sunscreen of choice for my arms and legs when I’m going on a ride. It provides good protection, and is long-lasting. For my face? I like Obagi’s sunscreen and also TIZO3, which has non-nanoparticle titanium dioxide and zinc oxide.
Bottom Line: Use Sunscreen
There have been recent controversies over whether sunscreens are more harmful than “natural” sunlight, but these arguments have largely been swept away by scientific research. Unequivocally the use of sunscreen has been shown to reduce the effects of ultraviolet damage and, more importantly, skin cancers of all types. Simply put, short of avoiding ultraviolet light with either clothing or by staying indoors, using sunscreen is far superior to unprotected sun exposure.
As a dermatologic surgeon I treat skin cancer every single day. For the vast majority of patients, much of their sun exposure and resultant sun damage came from their years prior to age 20. One of the best legacies we can leave for our children is to insist that they use the best protection through their childhood years, especially during their teenage years when they are most likely to get sunburns. Think of it like smoking. We would not allow our children to smoke, so why should we allow them to expose themselves to another known carcinogen?
Questions related to Vitamin D frequently come up when discussing sun exposure. As you know, vitamin D is important for bone health among other things, and vitamin D is converted to its active form by sunlight. However, we know that sunlight is a carcinogen, and we also know that vitamin D is easily obtained through dietary sources, particularly dairy products. Additionally, many cereal products are also fortified with vitamin D. Other sources include fatty fish such as salmon, tuna, catfish and mackerel, as well as eggs and mushrooms.
What’s my bottom line? Wear good sunscreen, practice “safe sun” and decrease your risk of skin cancers. Please.
ABOUT THE AUTHOR
Dr. Larry Bishop attended Wright State University medical school and then served nine years in the Air Force as a flight surgeon. An long-time affiliate of MIMA and now Health First Physician Group, he specializes in cosmetic and surgical dermatology, including Mohs Micrographic Surgery, and non-surgical rejuvenation of the face. He has lectured on dermatologic surgery techniques both in the U.S. and in Europe. You may call Dr. Bishop at 321-751-9097, or CLICK HERE FOR MORE INFORMATION.